The one-woman show “Late Nite Catechism” started in Chicago in 1993, created by Vicki Quade and Maripat Donovan. Since then, the show has played all over the U.S. and other countries. After all these years, it is still a crowd-pleaser, and again packing the Playhouse at Westport.

The premise is simple – yet strikes fear in any former parochial school kid – a nun is taking over teaching a catechism class for Father Murphy, because it his regular poker night. The setting is a Catholic Grade School room.

Lead by a very sharp, funny and commanding comedienne, Mary Zentmyer is brilliant at handling the crowd and keeping order in her classroom.

So, what is this theatre reviewer/audience member supposed to make of this show, as my parents were “members” of the very liberal Protestant United Church of Christ? (!). I did not grow up with a background in any organized religion.

I learned quite a bit about the Catholic religion. You may think you know the answer to some of the questions, but I was surprised to find out that much information out there is false. Some questions Sister asked about included Pagan babies, the Stigmata, the Holy Trinity and What saint supposedly helps sell your house (and how does that happen?). Was St. Patrick Irish?

The show is at its best when Sister is interacting with the audience, and Zentmyer does it with aplomb and rapid-fire humor. She was previously in last holiday season’s “Sister’s Christmas Catechism: The Mystery of the Magi’s Gold,” and has been playing Sister, primarily in her hometown of Chicago, since 2000.

She makes the girls who are showing too much skin cover up their cleavage or legs with a large handkerchief. She gets chatty audience members to come up onstage and put their nose in a circle drawn on the blackboard, which is called the Circle of Silence.

She must always be addressed as Sister, and insists on proper grammar.

If you raise your hand to answer a question, you must state your full name. One unfortunate woman in the crowd refused to use her middle name, so she was forced to pray for forgiveness as she sat on a small child’s seat onstage.

A large group of women raised Catholic had way too much to drink, which incurred the Sister’s wrath. She was quite stern and strict with them, and they loved every minute.

Seeing Zentmyer expertly work her audience is a joy to watch.

There is plenty of fun to be had for everyone, no matter your religious background, even if you are an unbaptized heathen like me.

My one big problem with the show is, first, the show’s length. By the second act, the show starts to feel like it has overstayed its welcome. There is no real story arc or build to the show.

After all these years, “Late Nite Catechism” could use some serious editing. This is in no way a reflection of Zentmyer’s very fine performance.

The show started at 8 p.m., the first act is LONG, and then there was a 15-minute intermission. The second act lasted no more than about 20 minutes. When I left the theater, it was 10:30 p.m.

I wonder if the show is meant to be performed without an intermission. Could it be that Westport wanted more time to sell alcohol to an already inebriated crowd?

Another small complaint is that the Westport Playhouse did not provide any type of program for the show, not even a simple page with basic info, including Zentmyer’s bio.

The set design was nice, not remarkable, but works well for the show. The lighting design is very basic. And of course, Sister is attired in the traditional nun’s habit. I cannot give credit to the design or stage management team because zero info was provided.

In looked up past productions online, the set was designed by Marc Silva, with lighting design by Tom Sturge. Maybe they reprised their efforts?

One last note: Catholic saints are a major topic. One female saint, whose name I won’t mention, was truly a crazed martyr. Today, this nun would be in a mental hospital and hardly not saint material. Her story is one that you will never forget, no matter how hard you try!

Emery Entertainment, in association with Entertainment Events Inc., presents “Late Night Catechism” at The Playhouse@Westport June 7 through June 17. Tickets are available online at Metrotix.com, by phone: 314-534-1111, or at the Westport Playhouse box office one hour prior to showtime. Groups of 10 or more can call 314- 616-4455 for special rates. For more information, visit www.playhouseatwestport.com